In general, an electric motor (electrical rotary machine) which includes a substantially cylindrical stator fixed to a housing and a rotator rotating by rotating a magnetic field generated by the stator is known. As for a structure of the stator of the electric motor, as disclosed in JP2004-159476A (paragraph 0007, FIG. 1, 2) and JP2003-37968A (paragraph 0027, FIG. 1, 2), conventionally, the structure which includes a plurality of approximately linear teeth arranged in the periphery of the rotator and extends in a radial direction, and an exciting coil wound around each tooth is known.
However, in the structure of a conventional stator, when the number of turns of the exciting coil is increased in order to obtain larger motor torque, there is a problem that the size of the teeth needs to be extended in a radial direction and the electric motor becomes larger in size in a radial direction.
The present invention aims to provide an electrical rotary machine wherein the number of turns of an exciting coil can be increased without enlarging the machine in a radial direction.